Thermoplastic resins are plastics which are softened and plasticized by heating and are hardened by cooling. Thermoplastic resins are divided into: common plastics such as polyethylene, polypropylene, acrylic, styrene, and vinyl resins; and engineering plastics such as polycarbonate, polyphenylene ether, polyamide, polyester, and polyimide resins.
Thermoplastic resins are widely utilized numerous in applications, including various household supplies, office automation equipment, and electric and electrical appliances, owing to their superior processability and formability. There has been a continuous attempt to use a thermoplastic resin as a high value-added material by imparting specific properties as well as superior processability and formability to the thermoplastic resin, according to the kind and properties of the products in which the thermoplastic resin is used. In particular, there have been various attempts to impart electromagnetic wave shielding performance to a thermoplastic resin and utilize the electromagnetic wave shielding thermoplastic resin in the manufacture of automobiles, electric apparatuses, electronic assemblies, and electrical cables, among other products.
Electromagnetic wave shielding thermoplastic resin is conventionally prepared from an electromagnetic wave shielding thermoplastic resin composition obtained by mixing a thermoplastic resin with an additive, such as a metallic powder, a metal-coated inorganic powder, or a metallic fiber. To ensure a desired level of the electromagnetic wave shielding performance of the electromagnetic wave shielding thermoplastic resin, the additive, due to its high specific gravity, must be used in significantly large amounts. However, such a large amount of the additive used to improve electromagnetic wave shielding performance can cause deterioration in inherent characteristics (e.g., impact resistance) of the thermoplastic resin, thus making it impossible to practically use the electromagnetic wave shielding thermoplastic resin.